1. Field of the Invention
The present invention relates generally to a gauge assembly for use in a vehicle instrument cluster, and more particularly, to a gauge assembly with a twist lock mounting feature having an adaptable coil component.
2. Background and Summary of the Invention
Instrument cluster gauges, such as speedometers, tachometers, fuel and temperature gauges used in modem vehicles commonly include a pointer body or needle coupled to a permanent magnet. The magnet is generally carried in a plastic housing or bobbin, which is wrapped with wire coils. During operation of the vehicle, current flowing through the coils creates a magnetic field, and the magnet rotates within the housing to align itself in force balance relationship with the magnetic field. Since the pointer body rotates with the magnet, positioning of the pointer body is controlled by the direction and magnitude of the current in the coils. To provide for steady movement of the pointer body, a viscous fluid is carried in the housing to damp the rotational movement of the magnet.
Current gauge assembly designs include a plurality of post-like terminals which are inserted in gauge mounting clips which are provided on the circuit boards. The gauge assembly is typically mounted to the display panel using mounting screws. Typical gauges are disclosed in U.S. Pat. Nos. 5,219,135 and 5,631,419. A disadvantage of these types of gauges is that they require mounting screws to mount the gauges to the display panel, and thus require a considerable amount of labor for mounting the gauge to the instrument cluster assembly. In addition, the electrical contact through the terminal posts and the gauge clips can create problems due to intermittent contact.
Accordingly, it is an object of the present invention to provide an alternative mounting technique for mounting a gauge to an instrument cluster assembly. These and other objects of the present invention are obtained by providing a gauge assembly including a terminal carrier including a base portion, a head portion extending from a first side of the base portion, and a plurality of legs extending from a second side of the base portion. The head portion includes a pair of twist lock locking elements disposed on the side thereof. A bobbin and coil assembly is supported by the terminal carrier. The bobbin and coil assembly rotatably supports a spindle and magnet. A plurality of electrical terminals extend through the base portion of the terminal carrier and terminate at one end into a bent contact portion adjacent to the head portion. The bent contact portions engage electrical contact pads disposed on the printed circuit board. The electrical terminals have a second end electrically connected to a coil of the bobbin and coil assembly. A plurality of mounting bosses are provided on the back of the display panel to receive and guide the gauge assembly to its proper location.
Furthermore, it is an object of the present invention to provide an alternate method of incorporating the wire coil component of the coil and bobbin assembly within the metal housing of the gauge assembly. Currently, the attachment of the wire component to the electric terminals of the gauge assembly requires soldering of the electric terminal ends to the ends of the wire component. This increases the amount of time and labor required to complete the construction of the gauge assembly. Redesigning the coil wire component of the coil and bobbin assembly such that the assembly may be adapted to the metal housing without the need to solder or weld the ends of the wires, reduces the amount of time and effort necessary to incorporate the coil and bobbin assembly within the metal housing of the gauge assembly.
The gauge assembly of the present invention eliminates the need for gauge mounting clips on the circuit board, reduces problems due to intermittent contact through the gauge clips and provides a higher level of reliability with the twist/wipe contacts used in the present invention. Furthermore, the gauge assembly of the present invention eliminates mounting screws and the associated assembly labor. The gauge assembly design of the present invention also reduces the package height of the gauge assembly which in turn reduces the overall thickness of the instrument cluster.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.